Binders, including those attached in folders, traditionally have opposing ring halves that may separate and come together to form open or closed loops. The ring halves are received within holes punched through a stack of paper or the workpiece to be temporarily bound by the closed loops. Traditionally, ring binders have half rings mounted on the springs that are biased against each other by a cover. The ring halves may be pulled apart from each other, targeting the leaf springs to an opened position. The ring halves may also be pushed towards each other, targeting the leaf springs to a closed position. Typically, the ring halves will snap between the open and close positions.
U.S. Pat. No. 2,179,627 discloses a loose leaf binder with toggle plates mounted with a spring back. A handle rotates a pinion to move the toggle plates longitudinally relative to each other other, together with curved sheet rataining prongs attached to the toggle plates. As the toggle plates are moved, a projection cams a toggle plate to open the rings formed by the retaining process. Upon further rotation of the handle, the toggle plates are forced by the spring back to return their relative angle or position.